Dubbed SolarEagle, the unmanned plane is similar to Predator drones used by the U.S. military. But unlike drones, the SolarEagle would operate on solar power, enabling it to fly continuously above Earth at 60,000 feet or higher.

Preliminary designs look like a gigantic toothpick sculpture. Its 400-foot wingspan would be more than twice that of a standard 747 plane. The size is necessary, Nickol said, to attach the multitude of solar panels that will power the plane’s electric system.

Boeing beat out two competing aerospace companies — Lockheed Martin and Aurora Flight Sciences — to win the contract, which is administered under DARPA’s Vulture program.

The company is tweaking its design with the help of NASA, which manages the technical aspects of the contract. The prototype is scheduled to fly for 30 days in 2014 in New Mexico, Boeing spokesman Chris Haddox said.

“You’re not going to go up there at 65,000 feet and repair it, so it has to be long-lasting and durable,” he said.

DARPA officials did not return phone calls seeking comment, but Nickol said the agency hopes other federal agencies will eventually fund the program. The plane could be used for weather and climate studies, border patrols and disaster response, Nickol said.

The most likely benefactor, however, is the military.

While overall defense spending is dropping, the Navy, Air Force, Marines and Army are investing in unmanned aerial vehicles. Spending exceeded $1 billion last year and it is projected to steadily increase, according to an October report from Frost & Sullivan, a California-based market research firm.

“This is an area that’s not going to be cut,” said Brad Curran, an aerospace industry analyst at the firm.

Indeed, Nickol ticked off a laundry list of planes that other aerospace companies are developing. The industry’s growth is reminiscent of fighter jets built during World War II, when pilots tested dozens of different planes.

“It’s sort of the Wild West with these types of airplanes,” Nickol said.

The growth comes as the U.S. continues to pivot toward intelligence, reconnaissance and surveillance missions, particularly in the Middle East and other hot spots.

With a tentative payload capacity of 1,000 pounds, the SolarEagle will be able to carry multiple cameras or communication systems, Nickol said. At heights exceeding 60,000, it will be difficult for enemies to shoot down, he said.

Still, the plane’s development is not a given. A predecessor called Helios flew several successful demonstrations before breaking apart and falling into the Pacific Ocean in 2003.

Also, proponents of unmanned aerial vehicles tout their money-saving potential; but there are back line expenses, such as plane maintenance and data processing, that make it difficult to determine how cost-effective they acturally are.